Wideband multifunction radars are capable of concurrently performing hemispheric surveillance, tracking and simultaneously illuminating multiple targets in diverse environments. It is widely recognized that only active phased array antenna and radar systems with their inherent waveform flexibility, high stability and beam switching speed can successfully cope with this broad mission.
For the control of phased array radars, photonic architectures can be broadly characterized as either optically coherent or non-coherent. Although optically coherent architectures have been laboratory demonstrated on a limited scale, their application to a tactical system, where thousands of optical signals must be phase locked is not practical.
The performance issues facing active phased array radars are radio frequency (RF) bandwidth (shared multifunction apertures, imaging, adaptive nulling), true time delay steering (wide instantaneous bandwidth), electromagnetic interference (EMI) and beam steering control. Realizable active arrays providing this performance are limited in weight and size and are generally costly. In particular, transmit/receive T/R modules and array substructures are key cost drivers.